NEW 232673
CSS outlines in contenteditable elements causes performance issues 
https://bugs.webkit.org/show_bug.cgi?id=232673
Summary CSS outlines in contenteditable elements causes performance issues
Brian Kim
Reported 2021-11-03 11:15:45 PDT
Created attachment 443215 [details] Safari Devtools timeline dump Typing in contenteditable elements is slow when using the default focused outline CSS rules. Steps to reproduce: 1. Go to https://www.slatejs.org/examples/plaintext 2. Inspect the contenteditable element and disable the `outline: none` style. 3. Try inserting many newlines using the Enter key. 4. When there is a visible outline, you should see noticeable lag and frame drops as the document size increases. 5. This lag does not exist when the `outline: none` style is re-enabled. I’ve attached a timeline export from Safari Devtools. The important detail is that in the frames view, Devtools reports that time is spent in Other (not Layout, Painting, Scripting). I do not have the ability to investigate further at this time.
Attachments
Safari Devtools timeline dump (29.27 MB, application/json)
2021-11-03 11:15 PDT, Brian Kim 		no flags
Details
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Radar WebKit Bug Importer
Comment 1 2021-11-10 10:16:35 PST
<rdar://problem/85259554>
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